大型泵站裂缝成因分析及处理

结合南水北调工程中某大型泵站的设计、施工情况,从结构设计、原材料选用、温度控制、混凝土超强、施工工艺及方案等方面对裂缝成因进行了定性分析,并利用三维有限元仿真计算成果对裂缝成因进行了定量分析。总结出大型泵站容易产生裂缝的部位、类型及原因,认为进水流道混凝土降温过程中出现的较大温度应力是早期裂缝出现的直接原因,采用的施工方案和泵送混凝土工艺是导致裂缝出现的间接因素。由于后期养护和保温措施不力产生较大的收缩应力和温度应力是引发中后期裂缝的主要原因。提出了从工程设计、原材料选用、温度控制、施工工艺及方案等方面采取综合防裂措施和处理裂缝的方法。

Causes of formation of cracks in large pumping station and measures for their treatment

Combining with the design and construction of a large pumping station in the South-to-North Water Transfer Project, a qualitative analysis was performed of causes of cracks from aspects of structure design, selection of raw materials, temperature control, excessive strength of concrete, techniques and scheme of construction, etc. , and a quantitative analysis was made by using 3-D finite element simulation. Then, the distribution, development and classification of cracks were summarized. It is considered that the large thermal stress in concrete during temperature decrease in the intake channel is the direct cause of the formation of the cracks at early stage, while the construction scheme and the technique of pouring concrete by pump are the indirect causes. The large shrinkage stress and thermal stress induced by ineffective measures for concrete curing and temperature insulation are the main causes at middle and later stages. Finally, it is suggested that integrated measures for crack prevention and crack treatment should be taken for engineering design, selection of raw materials, temperature control, and determination of reasonable scheme and techniques.